String gen

Generate random strings from regular expression patterns.

string-gen takes a regex pattern and produces random strings that match it. Common use cases include:

• Test data generation — create realistic inputs for unit and integration tests
• Fixtures — produce parameterized test fixtures on the fly
• Fuzzing — generate semi-structured random inputs for fuzz testing
• Mock data — build placeholder data for prototyping and demos

Documentation | API Reference | Cookbook

Installation

pip install string-gen

Quick Start

from string_gen import StringGen

# Basic generation
gen = StringGen(r'(A|B)\d{4}(\.|-)\d{1}')
gen.render()  # e.g. 'B9954.4'

# List of strings
gen = StringGen(r'[A-Z]{3}-\d{3}')
gen.render_list(5)  # e.g. ['XKR-839', 'BNQ-271', 'JYL-054', 'WMT-692', 'AFZ-418']

# Built-in patterns
from string_gen.patterns import UUID4, IPV4
StringGen(UUID4).render()  # e.g. '52aabe4b-01fa-4b33-8976-b53b09f49e72'
StringGen(IPV4).render()   # e.g. '192.168.1.42'

# Custom alphabets
from string_gen.alphabets import CYRILLIC
StringGen(r'\w{10}', alphabet=CYRILLIC).render()  # e.g. 'ёЩкРблнЫйМ'

For full documentation visit tolstislon.github.io/string-gen.

Changelog

• Releases

Contributing

Contributions are very welcome. You might want to:

• Fix spelling errors
• Improve documentation
• Add tests for untested code
• Add new features
• Fix bugs

Getting started

• Python 3.8+
• uv

1. Clone the repository

   git clone https://github.com/tolstislon/string-gen.git
   cd string-gen

2. Install dev dependencies

   uv sync

3. Run ruff format

   uv run ruff format

4. Run ruff check

   uv run ruff check --fix

5. Run tests

   uv run pytest tests/